diff --git a/packages/core/src/runtime/wait-continuation.test.ts b/packages/core/src/runtime/wait-continuation.test.ts
index 3d79cd5b91..25ac6fe594 100644
--- a/packages/core/src/runtime/wait-continuation.test.ts
+++ b/packages/core/src/runtime/wait-continuation.test.ts
@@ -9,18 +9,21 @@ const CORR_ID = 'wait_01ABC';
 const NOW = new Date('2026-05-19T12:00:20.500Z').getTime();
 
 describe('getWaitContinuationDispatch', () => {
-  describe('mid-range waits (bare correlationId key)', () => {
-    it('uses the bare correlationId so re-observations dedupe', () => {
-      expect(getWaitContinuationDispatch(60, CORR_ID, NOW)).toEqual({
-        delaySeconds: 60,
-        idempotencyKey: CORR_ID,
-      });
+  describe('mid-range waits', () => {
+    it('keeps the delay and prefixes the key with the correlationId', () => {
+      const { delaySeconds, idempotencyKey } = getWaitContinuationDispatch(
+        60,
+        CORR_ID,
+        NOW
+      );
+      expect(delaySeconds).toBe(60);
+      expect(idempotencyKey.startsWith(`${CORR_ID}:`)).toBe(true);
     });
 
-    it('is stable across suspension passes targeting the same deadline', () => {
+    it('PROBE: does NOT dedupe across suspension passes', () => {
       const pass1 = getWaitContinuationDispatch(60, CORR_ID, NOW);
       const pass2 = getWaitContinuationDispatch(45, CORR_ID, NOW + 15_000);
-      expect(pass2.idempotencyKey).toBe(pass1.idempotencyKey);
+      expect(pass2.idempotencyKey).not.toBe(pass1.idempotencyKey);
     });
 
     it('covers the full band up to the max delay', () => {
@@ -34,35 +37,28 @@ describe('getWaitContinuationDispatch', () => {
         CORR_ID,
         NOW
       );
-      expect(low.idempotencyKey).toBe(CORR_ID);
-      expect(high).toEqual({
-        delaySeconds: WAIT_CONTINUATION_MAX_DELAY_SECONDS,
-        idempotencyKey: CORR_ID,
-      });
+      expect(low.idempotencyKey.startsWith(`${CORR_ID}:`)).toBe(true);
+      expect(high.delaySeconds).toBe(WAIT_CONTINUATION_MAX_DELAY_SECONDS);
+      expect(high.idempotencyKey.startsWith(`${CORR_ID}:`)).toBe(true);
     });
   });
 
-  describe('near-elapsed waits (second-bucketed key)', () => {
-    it('suffixes the key with the current epoch second', () => {
-      expect(
-        getWaitContinuationDispatch(
-          NEAR_ELAPSED_WAIT_THRESHOLD_SECONDS,
-          CORR_ID,
-          NOW
-        )
-      ).toEqual({
-        delaySeconds: NEAR_ELAPSED_WAIT_THRESHOLD_SECONDS,
-        idempotencyKey: `${CORR_ID}:${Math.floor(NOW / 1000)}`,
-      });
+  describe('near-elapsed waits', () => {
+    it('keeps the full remaining time as the delay', () => {
+      const { delaySeconds, idempotencyKey } = getWaitContinuationDispatch(
+        NEAR_ELAPSED_WAIT_THRESHOLD_SECONDS,
+        CORR_ID,
+        NOW
+      );
+      expect(delaySeconds).toBe(NEAR_ELAPSED_WAIT_THRESHOLD_SECONDS);
+      expect(idempotencyKey.startsWith(`${CORR_ID}:`)).toBe(true);
     });
 
-    it('collapses same-second duplicates but frees the key for a later retry', () => {
+    it('PROBE: does NOT collapse same-second duplicates', () => {
       const first = getWaitContinuationDispatch(1, CORR_ID, NOW);
       const sameSecond = getWaitContinuationDispatch(1, CORR_ID, NOW + 400);
-      // A retry can only be enqueued after the >= 1s delay of the first
-      // message, which guarantees a later epoch-second bucket.
       const retry = getWaitContinuationDispatch(1, CORR_ID, NOW + 1000);
-      expect(sameSecond.idempotencyKey).toBe(first.idempotencyKey);
+      expect(sameSecond.idempotencyKey).not.toBe(first.idempotencyKey);
       expect(retry.idempotencyKey).not.toBe(first.idempotencyKey);
     });
   });
@@ -70,21 +66,24 @@ describe('getWaitContinuationDispatch', () => {
   describe('waits beyond the max delay (chained hops)', () => {
     const SEVEN_DAYS = 7 * 24 * 3600; // 604800s > 7 * MAX_DELAY (579600s)
 
-    it('clamps the delay to the max and suffixes the key with the hop index', () => {
-      expect(getWaitContinuationDispatch(SEVEN_DAYS, CORR_ID, NOW)).toEqual({
-        delaySeconds: WAIT_CONTINUATION_MAX_DELAY_SECONDS,
-        idempotencyKey: `${CORR_ID}:hop-8`,
-      });
+    it('clamps the delay to the max and retains the hop index in the key', () => {
+      const { delaySeconds, idempotencyKey } = getWaitContinuationDispatch(
+        SEVEN_DAYS,
+        CORR_ID,
+        NOW
+      );
+      expect(delaySeconds).toBe(WAIT_CONTINUATION_MAX_DELAY_SECONDS);
+      expect(idempotencyKey.startsWith(`${CORR_ID}:hop-8:`)).toBe(true);
     });
 
-    it('keeps the key stable for re-observations within the same hop window', () => {
+    it('PROBE: does NOT dedupe re-observations within one hop window', () => {
       const pass1 = getWaitContinuationDispatch(SEVEN_DAYS, CORR_ID, NOW);
       const pass2 = getWaitContinuationDispatch(
         SEVEN_DAYS - 3600,
         CORR_ID,
         NOW + 3600_000
       );
-      expect(pass2.idempotencyKey).toBe(pass1.idempotencyKey);
+      expect(pass2.idempotencyKey).not.toBe(pass1.idempotencyKey);
     });
 
     it('produces a fresh key at each hop delivery so the chain advances', () => {
@@ -107,7 +106,7 @@ describe('getWaitContinuationDispatch', () => {
       expect(new Set(keys).size).toBe(keys.length);
       // 604800s chains as 7 max-delay hops + 1 remainder hop.
       expect(keys).toHaveLength(8);
-      expect(keys[keys.length - 1]).toBe(CORR_ID);
+      expect(keys[keys.length - 1]?.startsWith(`${CORR_ID}:`)).toBe(true);
     });
 
     it('uses a fresh key when the final partial hop lands in the near-elapsed band', () => {
@@ -118,7 +117,7 @@ describe('getWaitContinuationDispatch', () => {
         CORR_ID,
         NOW + SEVEN_DAYS * 1000
       );
-      expect(nearEnd.idempotencyKey).toMatch(new RegExp(`^${CORR_ID}:\\d+$`));
+      expect(nearEnd.idempotencyKey.startsWith(`${CORR_ID}:`)).toBe(true);
     });
   });
 
diff --git a/packages/core/src/runtime/wait-continuation.ts b/packages/core/src/runtime/wait-continuation.ts
index 59b3765c06..02ae2e0036 100644
--- a/packages/core/src/runtime/wait-continuation.ts
+++ b/packages/core/src/runtime/wait-continuation.ts
@@ -1,6 +1,12 @@
 /**
  * Wait-continuation dispatch: delay + idempotency-key selection.
  *
+ * !! PROBE BRANCH — NOT FOR MERGE !!
+ * Dedupe is disabled: every key gets a unique suffix, so no enqueue is ever
+ * collapsed. The rest of this comment describes the behaviour this branch
+ * deliberately removes; read it as the rationale under test, not as what the
+ * code now does. See `uniqueSuffix` below.
+ *
  * When V2 suspension processing observes a pending wait, it enqueues a
  * delayed "continuation" message that fires once the wait elapses and
  * drives the next replay (which completes the wait via the "complete
@@ -101,6 +107,22 @@ export interface WaitContinuationDispatch {
  * (floored at 1s by the suspension handler); `waitCorrelationId`
  * identifies the wait so repeated suspension passes dedupe.
  */
+/**
+ * PROBE (not for merge): makes every continuation key unique, disabling
+ * dedupe.
+ *
+ * A key is still attached because its absence is not neutral — some worlds
+ * (world-postgres) serialize key-less workflow messages per run, which would
+ * park the continuation behind the handler's own inline step execution. This
+ * keeps a key and only removes its collapsing property.
+ *
+ * The counter covers two enqueues within the same millisecond in one process;
+ * `Math.random` covers concurrent processes.
+ */
+let probeCounter = 0;
+const uniqueSuffix = (now: number): string =>
+  `${now}-${(probeCounter++).toString(36)}-${Math.random().toString(36).slice(2, 10)}`;
+
 export function getWaitContinuationDispatch(
   timeoutSeconds: number,
   waitCorrelationId: string,
@@ -120,7 +142,7 @@ export function getWaitContinuationDispatch(
   if (timeoutSeconds <= nearElapsedThreshold) {
     return {
       delaySeconds: timeoutSeconds,
-      idempotencyKey: `${waitCorrelationId}:${Math.floor(now / 1000)}`,
+      idempotencyKey: `${waitCorrelationId}:${uniqueSuffix(now)}`,
     };
   }
 
@@ -128,6 +150,8 @@ export function getWaitContinuationDispatch(
   return {
     delaySeconds: Math.min(timeoutSeconds, maxDelaySeconds),
     idempotencyKey:
-      hop === 1 ? waitCorrelationId : `${waitCorrelationId}:hop-${hop}`,
+      hop === 1
+        ? `${waitCorrelationId}:${uniqueSuffix(now)}`
+        : `${waitCorrelationId}:hop-${hop}:${uniqueSuffix(now)}`,
   };
 }